MuSiNgS

Tuesday

With the launch of the seventh and last satellite of the Indian Regional Navigation Satellite System (IRNSS) on Thursday, India joined a select club of countries with their own global positioning systems.

Thursday

When India launches its maiden Aditya-1 Mission, it will further illuminate our understanding of the sun

Photo: Bruno Caimi

Though the sun marks the difference between a habitable world and a barren wasteland, we are only beginning to understand the various dynamics of our parent star. The yellow ball of gas that brightens up our days (and nights) shapes the physical processes on Earth and sustains our foodchain. Earth’s climate is governed by the sun and the sun’s variability is a hotly debated issue in climate science. For instance, the Little Ice Age of 1816 was the result of a mere one degree fall in global temperatures. “1816 came to be known as the year without summer. Crops failed to grow. In Ireland, a famine and a subsequent typhoid epidemic killed 65,000 people,” says Bill Bryson in A Short History of Nearly Everything.

More than 20 international space missions are trying to understand sun’s structure and composition. Now India is gearing up to launch its maiden mission, Aditya-1, which will be launched in 2019-2020. More than 50 solar scientists from 10 institutions across the country are working round the clock to shield us from the impacts of unruly space weather and sun’s variability on Earth’s climate. When Aditya-1 is launched, India will join a select group, which includes USA, Japan and the European Space Agency, that have sent missions to the sun.

“Our primary objective is to study the solar corona, processes leading to changes in it, and to understand what heats the corona. Observations of sun’s photosphere, chromosphere and corona are also possible,” says Deviprasad Karnik of the Indian Space Research Organisation (ISRO), which is leading the mission.

The corona is the outermost layer of the sun’s atmosphere, preceded by the chromosphere and photosphere respectively. “The mission will provide a multipronged holistic approach to understanding some of the outstanding problems of solar physics,” says Karnik (see ‘Sun surfing’).

“We are in the process of designing the payloads. Aditya-1 will be launched from Sriharikota, an island off Sullurupeta, a sm-all town in Nellore district, Andhra Pradesh,” Karnik says.

The other institutes working on Aditya-1 include the Indian Institute of Astrophysics, Bengaluru, which is working on the Visible Emission Line Coronagraph (see interview), the Physical Research Laboratory, Ahmedabad, which is working on the Aditya Solar Wind Particle Experiment and the Vikram Sarabhai Space Centre, Thiruvananthapuram, which is working on Plasma Analyser Package for Aditya.

When the mission was first conceptualised in 2008, its launch was envisioned to coincide with solar maxima—a period of intense sun activity that occurs every 11 years. However, it was later decided that the satellite would be placed in a halo orbit around lagrangian point 1, which is 1.5 million km from Earth (where a satellite can maintain its position with respect to other bodies). “The initial concept was to put the coronagraph payload in a small satellite in an 800 km low Earth orbit. Aditya-1 is an updated version of the original Aditya mission with six additional payloads,” adds Karnik.

The advantages of placing the satellite in a halo orbit are many. Situated outside Earth’s atmosphere and magnetosphere, it remains unaffected by Earth. A halo orbit also ensures that there is no occultation for the spacecraft’s line of sight. Moreover, a satellite placed in a halo orbit experiences much less mechanical and thermal disturbances, and is, therefore, more stable.

What past missions have found

Other sun missions have added gravity to our understanding of the sun. The Solar and Heliospheric Observatory (SOHO), a collaboration between the European Space Agency and the National Aeronautics and Space Administration (NASA), celebrated its 20th anniversary on December 2, 2015. “SOHO changed our popular view of the sun from a picture of a static, unchanging object in the sky to the dynamic beast it is. It showed us what we had never seen before. We realised we need more eyes on the sun,” says Bernhard Fleck, a project scientist with SOHO.

This gave birth to a plethora of space-based solar observatories: Hinode, the Solar Dynamics Observatory (SDO), the Interface Region Imaging Spectrograph and the Solar and Terrestrial Relations Observatory. NASA’s SDO has been recording the sun’s dynamic solar activity since its launch on November 2, 2011 (see ‘Light alight’).

“The scientific objective of the SDO mission was to understand the lifecycle of the solar magnetic field. We wanted to understand how the sun’s magnetic field is generated, how it moves around the sun, and how it is destroyed. With this understanding, we sought to develop the science needed to predict solar activity,” says Dean Pesnell, a project scientist with SDO.

ASPEX: Will study the variation, distribution and spectral characterstic of solar windWHY: Solar wind can affect our power lines, communication satellites and high altitude spacecraft

VELC: Will study the parameters of the solar corona and origin of Coronal Mass Ejections (CMEs)WHY: CMEs can collide with Earth's magnetic field and change its shape

SUIT: Will image the photosphere and chromosphere in UV rangeWHY: A better understanding can help us keep track solar flares emanating from the photosphere

SoLEXS: Will monitor X-ray flares to study the heating mechanism of the coronaWHY: Energy from X-ray flare can disrupt radio waves, causing blackouts in navigation and communications signals

PAPA: Will study the composition of solar wind and its energy distributionWHY: Solar wind can disrupt communication and navigation satellites

HEL1OS: Will observe the dymanic events in the corona and estimate the energy used to accelerate the particles during the eruptive eventsWHY: An estimate of the energy can help us shield ourselves in an effective and timely manner

Predicting solar activity assumes immense significance. On the night of September 2, 1859, the world woke up to red, green and purple auroras that had erupted nearly everywhere on Earth and not just at the poles where they are a characteristic feature. Telegraph systems were disrupted as the world witnessed its first recorded solar flare, also known as the solar storm of 1859. And as recently as on July 23, 2012, a solar storm, touted to be as strong as the one in 1859, was predicted. Fortunately, we missed it by a week—Earth had moved ahead in its orbit.

Disruptions in the solar atmosphere and surface can also cause a flurry of solar activity that affects space weather. A better understanding of the sun can also help in aeronautics (high-altitude aircraft exposure to radiation), astronautics (radiation threat to astronauts and spacecrafts) and technology infrastructure development (effects of radiation on communication satellites).

As new frontiers in scientific enquiry are being conquered, they are only throwing up more questions. “The next frontier in our understanding of the sun is to measure its polar regions with the same instrumentation we use near the equator. At present, we have very few measurements from above the poles,” says Pesnell. “Better predictions will lead to a more cost-effective response. Power plants that will be affected can be isolated; satellites can be tuned to power off sensitive high-voltage components, and, astronauts in deep space can get into a safe shelter before the danger arrives,” adds Pesnell.

Aditya-1 will hopefully reveal, among other things, why the solar corona heats up to temperatures of a million degrees or so, much higher than the visible outer layer of the sun’s surface—the photosphere. Findings that will unlock the secrets to our understanding of our parent star.

`Aditya-1 will take images every second'

Dipankar Banerjee of the Indian Institute of Astrophysics (IIA), Bengaluru, which is one of the institutions working on Mission Aditya-1, speaks to Down To Earth

What specific area of the mission is the IIA working on?

IIA is making the Visible Emission Line Coronagraph (VELC), which is one of the main payloads. Coronagraph creates an artificial total solar eclipse in space by blocking the sunlight by an occultor. This telescope will have capabilities of spectral imaging of the corona in visible and infra-red. We are in phase 1 of the mission. Design and review are almost complete.

What is going to be the payload capacity of the mission?

The coronagraph is the biggest payload occupying 60 per cent of weight of the instruments on board Aditya-1. Using this payload, we want to study the dynamic changes in the sun.

How is Aditya-1 different from previous missions to the sun?

Aditya-1 is a multi-wavelength observatory which will look at different layers of the solar atmosphere. Aditya-1 is different in many ways. Take NASA's STEREO. It has two coronagraphs and one imager. The coronagraphs on board STEREO take images every 10 minutes, and probes only at the outer corona. Aditya-1's VELC, on the other hand, will look at the inner corona and will take images every second.

Tuesday

Indian Space Research Organisation (ISRO) is all set to launch a new earth observatory named CartoSat-2C in May. The satellite built for military purposes will blast off using the renowned PSLV (Polar Satellite Launch Vehicle). After the launch, India will join the ranks of China and USA who have their own spy satellites to monitor activities on Earth from space.

Indian space scientists built the satellite at the Space Applications Centre (SAC) in Ahmedabad. Several rounds of tests were performed to check the durability and functioning of the satellite. Two weeks ago, CartoSat-2C was shifted to ISRO Satellite Centre (ISAC) at Bengaluru. India’s first dedicated military satellite — CartoSat-2A was launched in 2007 and since then it has given very sensitive and highly classified information including the missile launches in the neighbourhood.

According to the official report, the satellite weighs 690 kilogram. The high-resolution multi-spectral instrument and Panchromatic Camera will enable the satellite to capture some stunning high-resolution images. Previous military satellite had the resolution of 0.8 metre while the new camera installed on the CartoSat-2C has a resolution of 0.65 which means that it can spot even smaller objects from space. What’s striking about the camera of the new satellite is that it has the capability to record videos, process it to reduce size of the file and then beam it back to the Earth.

CartoSat-2C will blast off along with 21 other satellites using PSLV rocket in May this year. It will be placed in a sun-synchronous polar orbit at a low-earth altitude of about 200-1,200 kms above the Earth’s surface. Once launched, it will be one of the finest eyes present in space.

ISRO officials describe this satellite “as one of the best eyes in space” that India has launched till date. The strength of the camera installed in this home-grown satellite is almost at par with the ones possessed by US and China. For instance, in 2014, the Chinese had set a remote sensing satellite “Yaogan 24” which had a similar camera of 0.65 metre resolution. The panchromatic imagers can not only be used for surveillance, but can also aid in disaster monitoring. It will also click images that can give an idea of temperatures of a particular location in comparison with the surrounding areas. Cartosat-2C is expected to be launched along with 21 other satellites in May using a PSLV rocket. It will be placed in a sun-synchronous polar orbit at a low-earth altitude of about 200-1,200 kms above the Earth’s surface. - See more at: http://indianexpress.com/article/cities/ahmedabad/cartosat-2c-to-boost-military-surveillance-capabilities/#sthash.IugXyw6r.dpuf

India has secretly conducted the maiden test of its nuclear capable undersea ballistic missile, code named K-4, from homegrown submarine INS Arihant at an undisclosed location in the Bay of Bengal.

The test conducted on March 31 nearly 45 nautical miles away from Vishakhapatnam coast in Andhra Pradesh was highly successful. The indigenously developed weapon with a dummy payload was reportedly launched from the submarine in full operational configuration.

KILLER K-4

Intermediate Range SLBM

Operational Range – 3,500 km

Length – 12 meter

Width – 1.3 meter

Weight – 17 tonne

Warhead – 2,000 kg

Engine – Solid fueled

Accuracy – Near zero CEP

The trial was carried out with the support of the personnel of Strategic Forces Command (SFC) while the DRDO provided all logistics. The missile was fired from 20-meter deep and it pierced into the sky after breaking the water surface. INS Arihant had first successfully fired a prototype of K-15 (B-05) missile in November last year.

The K-4 missile was fired from onboard silos of the ship submersible ballistic, nuclear (SSBN) submarine demonstrating the capability of the newly built underwater warship to fire long range nuclear capable missiles and the killing efficiency of the most advanced state-of-the-art weapon system.

“Having an operational range of nearly 3,500 km, the missile was fired towards north for a shorter range. It covered more than 700 km before zeroing on the target with high accuracy reaching close to zero circular error probability (CEP),” informed the source.

On March 7, this missile was test fired from a submerged pontoon (replica of a submarine) positioned nearly 30 feet deep sea offshore Vizag coast. Although, the DRDO didn’t officially confirm about the secret mission, it was learnt that the test was a roaring success.

Even as the DRDO had reportedly conducted the first test of the missile system, which was developed under a secret project, in 2010, it officially admitted to have a missile named K-4 with a video footage of the missile launch in the Aero-India show in January last year.

Reports indicated the K-4 missile with the features of boost-glide flight profiles is designed to defeat any anti-ballistic missile systems. Equipped with the satellite updates to modify accumulated errors from its inertial navigation system, the weapon system is claimed to be quite dangerous and one of its kind in the world.

The 111-metre-long INS Arihant has four vertical launch tubes, which are capable of carrying 6 torpedoes of 533 mm and 12 B-05 (K-15) missiles or 4 K-4 missiles.

Powered by an 85 MW capacity nuclear reactor with enriched uranium fuel, this submarine can achieve surface speeds of 12 knots to 15 knots, and submerged speeds of up to 24 knots, carrying a crew of 95.

Apart from Arihant, the K-4 will also arm another Arihant class submarine INS Aridhaman which is currently under construction along with two others. These submarines will have eight launch tubes each.

India’s Defense Research and Development Organization (DRDO) has once again test-fired the K-4 nuclear-capable submarine-launched ballistic missile (SLBM)–this time from aboard the Indian Navy’s indigenously built nuclear submarine, the INS Arihant, the first submarine in its class. In March 2016, DRDO had successfully tested the K-4 from a submerged platform in the Bay of Bengal.

According to the New Indian Express, the Arihant-based K-4 test was “conducted on March 31 nearly 45 nautical miles away from Vishakhapatnam coast in Andhra Pradesh.” The K-4 missile was fired from theArihant‘s onboard SLBM silos.

India’s K-4 is an intermediate-range, nuclear-capable, submarine-launched ballistic missile. Though official details remain scarce given the project’s sensitivity, most estimates place the K-4′s range at roughly 3,500 kilometers. Recent testing of the K-4 has sought to test the full operational range of the missile. The DRDO scientists’ purported aim this week is to test the full operational range of the missile. During a previous test in March 2014, where the weapon was ejected from the submerged pontoon by a powerful gas generator, the K-4 was only tested to a range of 3,000 kilometers (1,864 miles). In addition to its range, recent testing as sought to test the SLBM’s accuracy. Claims by DRDO scientists and publicly available information on the system suggest that the K-4 is a highly accurate system. As Franz has discussed, DRDO scientists have boasted that the K-4 has “near zero circular error probability” and uses “a Ringer Laser Gyro Inertial navigation system.”

The K-4, along with the K-15 Sagarika SLBM, will give the Arihant-class of nuclear submarines their nuclear strike capabilities, allowing India to field an undersea nuclear deterrent capability. The K-15 has a considerably shorter range than the K-4. At a maximum strike range of approximately 750 kilometers, Arihant-class submarines would have to move close to enemy shores to successfully deploy the K-15 SLBMs, increasing the odds of detection. The intermediate-range K-4 helps rectify this shortcoming. The K-4 is capable of carrying both conventional and nuclear payloads in excess of 2,000 kilograms.

The Indian Navy anticipates commissioning the first Arihant-class submarine in 2016. The Indian Navy anticipates eventually fielding a force of three to six Arihant-class submarines. INS Aridhaman, in construction, will be the second submarine of the Arihant-class. Each submarine will be able to carry 12 K-5 Sagarika missiles and 4 K-4 SLBMs. With the Arihant‘s commissioning, the Indian Navy will join the navies of the United States, the United Kingdom, France, Russia, and China in operating nuclear-powered ballistic missile submarines.

Wednesday

Arihant has completed all tests including
deep dive and weapon firing tests past five months in secrecy. Two more such
SSBNs with bigger payloads, more advanced features and size are already under
construction with two more planned for a total of five. India does not have a
submarine rescue vehicle hence Russian Prut class vessel Epron accompanied
Arihant for the deep dive tests. Arihant submarine can carry K4 missiles
equipped with nuclear weapons, MIRV possibility, with a range of 3500 KM.This manoeuvrable
missile having an innovative system of interlacing in three
dimensions can also cruise at hypersonic speed. This exceptional feature of the
weapon system makes it difficult to be tracked easily and destroyed by any
anti-ballistic missile defence systems. The missile has a high accuracy of near-zero circular error probable. India has so far planned three missiles in the K-series. While the 700-km
range K-15, renamed as B-05 (launched 10 times) and 3,500-km range K-4 have
been developed, the K-5 will have a striking capability of over 5,000 km. All the K-series missiles are faster, lighter and stealthier. India currently operates one nuclear submarine INS Chakra, Akula class
SSN leased from Russia.

Friday

Indian Space Research Organisation (Isro) on Tuesday created a quiet bang that would soon propel India into a bigger league of nations launching satellites weighing up to five tonnes.

In a silent operation at the Mahendragiri test facility, Isro successfully test-fired the indigenous cryogenic engine CE-20 for 645 seconds. This marks a milestone in the country's effort to develop a big cryogenic engine to fly the ambitious GSLV-Mark III by the end of 2016.

In the absence of a proven indigenous cryogenic engine, India has been dependent on foreign space agencies like Arianne for the launch of heavy communication satellites. India's ambitious manned space programme also rests on the shoulders of GSLV-Mark III. A senior space scientist told that the 645-second test is a big boost since shorter duration tests did not put the engine to a complete resilience test. "This means that we will be ready for a stage test (after integrating the engine with the upper stage) in six months. If everything goes right, we should be able to fly a GSLV-Mark III by the end of next year," said the scientist.

But there are challenges. "Soon we will have to do a high altitude test, simulating low pressure atmosphere on ground to see how the engine behaves," said the scientist. Cryogenic technology has remained a challenge for all space-faring nations because of its complexity. A cryogenic engine uses Hydrogen as fuel, stored at minus 253 degrees Celsius and liquid oxygen as oxidizer at minus 183 degrees Celsius.

So far India's GSLVs were being powered by cryogenic engines given by Russia. Of the seven such engines, Isro has used up six. India's first attempt with an indigenous cryogenic engine was a failure. The second flight was a success, but that engine had a much lower thrust, about seven tonnes.

"CE-20 will be our trump card," said an engineer associated with India's programme for more than 20 years. "If we can fly GSLV-MIII by next year, we will not just be self-sufficient, but also be able to rake in big monies by doing commercial launches for other countries."